Hey all, need some help. It snowed last week where I live and so I put my car in the garage, hooked up my battery to a trickle charger and left it. Today roads are clear so I went to start it, started up right away but then just died after a second or so. Now it's flooded and will have to deflood when I get back home. But what is concerning is why would the car just shut off like that after being turned on?

Hope someone can help.

 

So I am thinking this is a coil issue, I had one replaced a couple years ago but they left the others in to save money. I am thinking the older ones are probably starting to fail and was expecting them to soon anyways. I did have other symptoms prior to this, for example once in a while the idle would go crazy, from normal idle at 750 RPM would drop to 500 RPM and shoot up to 1000 RPM, this is if I was stopped at a light. Also, gas mileage seems to be getting worse. No loss of power however, revs through the RPM's easily. Also, I do notice a longer start when cold as well, sometimes it will take a few seconds to come on and when it does its a bit harsh.

Could also be the engine I suppose as it's original, but I have never had an issue with hot starts except when the coils start going.

Hope to hear more thoughts on this.

 

I'd check your intake and see if you have a vacuum leak somewhere. What intake is on there?
Poor intake design or leaks can cause stuff like this.

Definitely plan to replace the coils. Sometimes engine death is the first symptom of a failing coil.

 

A few days ago I had a similar problem: it started well, but the engine failed at times, when I released the throttle, the idle went up and down, fell at 500 rpm and then went up 1000 or 1500. Suddenly something better went for a few kilometers and suddenly when I release the pedal to change gears, it fell back and came to stand.
I connected an ODB2 reader and with the data of the entire route to my work, I took a graph: I realized that the MAF sensor had huge variations, there were moments where it was going well and suddenly some strange peaks appeared and going well again .
He had recently cleaned the sensor and its connector, so it could not be dirt; however, it made me suspect the smoothness with which the connector came in and out so, with a very fine screwdriver, lift the pins of the female connector slightly so that they tighten more.
When you re-enter it, I noticed that it was much harder. I tried the car and it hasn't failed me again.
Throughout the life of the car, the pins of the MAF connector both remove and put it are losing pressure and become more sensitive to moisture and possible dirt. Your problem may be another, but I would not rule out this possibility.

 

Well now that it's getting warm again, tried getting her started but no go. It's cranking I can smell fcuel so I don't think the fuel pump is the problem (has a full tank of gas too). Tried to deflood, no go. So off to the dealership it goes.
I noticed on some of the posts here, they mention bad battery connectors. Would that give me this issue? I have power in the car, the lights radio windows etc all work. But I saw a few people say bad battery connectors can cause this issue. Would bad battery connectors cause the car to start and shut off right away? Also, MAF sensor seems to be another culprit. Either way guess I'll see what the dealership says. Hate taking it there cuz it's a rip off.
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Update:
Got Sexy Rexy back today. Good news: looks like I avoided an engine failure. The solution? Remove plugs and clean, clean cylinders and added oil to housing. Any idea what this means?
She runs great as always, great power, great acceleration, feels almost brand new to be honest. I am curious about adding oil to housing and what that exactly means.

 

the engine likely has compression issues and is due for replacement

the oil helps seal it up some when cranking, but is only temporary until it burns off.

just like when installing new tires, the slow degradation over time goes unnoticed until you go back to square one again. You only think it feels great.

.

 

Ugh, that is something I didnt want to hear. I mean, it feels great, has power and all but I guess this is likely a temporary fix then?

 

Uhh.. There is nothing cleanable in there. Certainly not cylinders. Squirting oil in the rotor housings gives you better sealing until the oil burns off.
Adding automatic trans fluid in there in small quantities as a carbon treatment has been attempted, and if thats what they did, it might have freed up a carboned up seal.

So depending on what they actually did, it could be as temporary as one run, or a few months or last a long time. I would just as soon get a compression test done and see where you stand.

 

Got a compression test done a couple years ago it was on the low end. So I pretty much know that the engine is on its last legs, even though it does run very well right now. I always assumed since I never had a hot start problem that it could last me a few more years but I figure it's just a matter of time. I already decided I'd drive it until it was done then sell the shell and get something new cuz spending $5000+ for a reman/rebuild makes no sense especially how the economy is right now.

 

Gonna call the tech tomorrow and ask exactly what they did. I don't even know if they know what they are doing o dont think rx8 even has cylinders lmao!

 

Took my car in and got the bad news - low compression. They replaced the spark plugs and said I needed to drive in 1st and 2nd getting up to 3,000 for a couple hundred miles to clean it out. I admit that since COVID I've hardly been driving, much less revving like I should have been. So I plan to get Seafoam and push it as much as I can while the weather's good and do more of the same in the spring. In fact I already put a couple cans in a quarter tank to start.

Should I have gotten the actual compression numbers to know how bad it is and to check on it later to see how it's changed? I'm not mechanically inclined but is there anything else I can do?

 

Yes getting the actual numbers is always a good start. They should still have them on file, if they did the test right? Was this a Mazda dealer?

Skeptical that seafoam will do anything, but it can't hurt. It definitely won't do anything if you just add it to the fuel, there's a decarbing procedure in the shop manual and Mazda used to perform this with their special inhouse cleaner. But in any case, it can't hurt.

Do you have symptoms? Are there actual problems that lead you to take in in the first place?

Getting up to 3000? You shouldn't drive this car *below* 3000 for the most part. Did you mean 9000?

I would recommend winding it out in 3rd, so you spend the most time at full throttle. That's what's important, not rpm.

 

Thanks - yeah, rough idle was the issue. I'd had an odd clicking sound that they finally resolved with a high mileage oil change but then this happened...ha!

So it does sound and feel a lot better with the new spark plugs but the dealership didn't sound optimistic. I have an automatic so they said to run it up to 3,000 rpm in manual when in 1st and 2nd gears. Obviously with an automatic it's more involved to get it up to 6,000 even on the highway for more than a few seconds.

They did not mention doing any specific service to remove the carbon buildup so my impression was that's not a standard "approved" thing for a dealership to do?

 

Decarbing is a standard mazda procedure but I think they stopped producing the cleaner they use because it's carcinogenic.

3000 will do nothing, you need to put the pedal to the floor and keep going until you run out of gear or safe speed. That burns off carbon. It's generally recommended to do make this a daily habit with rotaries.

But, get the real numbers if you can. That'll be more informative.

 

I think they're giving me super-conservative super-safe advice because they think they might get me to put in a new engine at the end of all this!

So, last question - is it too late to even bother with pre-mixing? Is that mostly preventative and won't do much at this point?

 

If it was my car, I would try to get a clearer understanding of the problem. Its possible the compression is low, but if you're not having hot start problems, it can't be that low. Once you have actual compression numbers (done using a rotary tester, which Mazda used, hopefully!), you can start planning remedies.

Driving on a bad ignition can cause the catalytic converter to clog, which will in turn kill the engine. So I would bring it somewhere (anywhere, it's not specific to Mazda), to have the cat examined internally to confirm it's not clogged/crumbled.

If all is well, and you have your new ignition then.. problem solved for the time being? Premix if you wish, it won't repair anything but may prolong useful engine life by providing more oil to seal the gaps through which compression is lost.

Wait until you have hot start issues before investing in engine replacement, who knows what will happen between now and then. You could also choose to sell it while it still runs, if that's your endgame should a new engine be necessary.